Combined protractor and t-square.



R. A. ROHRICH.

COMBINED PROTRACTOR AND T-SQUARE. APPLICATION FILED MAY 28. I9l5.

Patented Dec. 5, 1916.

Au -um I M lumn "ll Hill r T m: Nlmms PEYERS co.. PMom-Llnul. msmnumm n L RALPH A. RDHRICI-I, OF CLEVELAND, OI-IIO.

COMBINED PROTRACTOR AND T-SQUARE.

Specification of Letters Patent.

Patented Dec. 5, 1916..

Application filed May 28, 1915. Serial No. 31,013.

To aZZ whom it may concern:

Be it known that I, RALPH A. RoHRroH, a citizen of the United States, residing at Cleveland, in the county of Cuyahoga, State of Ohio, have invented certain new and useful Improvements in Combined Protractors and T-Squares; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

This invention relates to a combined protractor and T-square.

An object of the invention resides in the provision of a device which is constructed entirely of metal.

A further object of the invention resides in so constructing the device that it may be adjusted, readily, to various angles.

Astill further object resides in so constructing the device that after the blade has been set in angular relationship to the head it may be shifted from one side of the board to the other, thus producing the complemental angle.

A still further object of the invention resides in the provision of means on the blade for supporting a triangular scale out of contact with the paper, which means also acts as a brace for the blade.

With these and other objects in view, such as will appear as the description progrosses, my invention comprises the combination and arrangement of ,parts as set forth in and falling within the scope of the appended claim.

Referring to the drawing: Figure 1 is a plan view of a device constructed in accordance with my invention. Fig. 2 is a longitudinal sectional view. Fig. 3 is an elevation looking at the edge of the head from which the protractor support projects. Fig. 4 is an elevational view looking at the end of the blade.

Referring to the drawing wherein like parts are indicated by like characters throughout the several views.

In the embodiment of my invention shown in the drawing, I have provided a cross head 1 having an outwardly extending portion 2 on which a protractor 3 1S mounted. This head is of skeleton formation and has a flange 4 which extends completely around the edge thereof projecting from its lower face. Formed on the upper face of the head and in alinement with the straight edge thereof are lugs 5, the use of which will later appear.

Pivotally mounted on the upper face of the head 1 is a blade 6. This blade is pivoted to the head in the following manner: Extending through a hole in the head is a screw 7 on which a Washer 8 is mounted which bears against the under face of the said head. Adjustably mounted on the upper end of this screw is a winged nut 9 which has a shank 10 formed thereon, which shank, when the nut is tightened on the screw, will extend completely through a hole 11 in the blade 6 and partially through the hole in the head. The lower face of the wings of the nut will, at this time, bear against the upper "face of the blade and bind the said blade in position upon the head. The protractor is mounted on the head so that it will be concentric with the pivotal point of the blade. On the end of the blade adjacent the protractor is a pointer 12 which is adapted to cooperate with the said protractor to determine the angle at which the blade extends from the head.

In order that the blade may be strengthened and a bearing and guide for the base of a triangular scale provided, I have struck a rib 13 from the material of the blade, the blade being made of thin metal. The edges of this rib are parallel to the edges of the blade at right angles thereto and the rib extends upwardly from the blade. It will thus be seen that an angular scale may be rested upon the blade with its edge in contact with one edge of the rib and the said scale supported out of contact I ith the paper and yet in its proper position.

Now in the ordinary use of the device with the head 1 on the left hand edge of the drawing board the nut 9 is loosened and the blade 6 adjusted to the proper position by the use of the protractor 3. The nut 9 is then tightened and the blade positively maintained in its angular relationship. An angular scale may be rested against the edge of the blade or may be rested against the edge of the rib thereon, as desired. Now should it be desired to draw the reverse angle, it will only be necessary to shift the head 1 to the right hand edge of the drawing board and turn the device over. At this time the blade will rest upon the rib 6 and the lugs 5 will ongage the edge of the board. Thus the complemental angle may be used without necessitating the readjustment of the blade.

It will be seen that I have provided a device which will be made entirely of metal and yet Will be of such construction that it will be light and easily handled.

I have mounted a protractor on the head of the T-square which is concentric with the pivotal point of the blade so that the blade may be adjusted readily, to any angular position with relation to the head. Furthermore I have provided a strengthening rib on the blade, the edges of which are parallel to the' edges of the blade so that an angular scale may be rested onthe blade and against the edge of the rib so that it will be supported out of contact with the paper.

While I have illustrated and described a particular embodiment of my invention, I have merely done so for the sake of convenience and I do not wish to be limited to that particular embodiment as it is obvious that numerous changes may be made within the details of construction thereof without in any way departing from the spirit of the invention or exceeding the scope of the appended claim.

What I claim is:

A T-square provided with a relatively wide blade and a relatively narrow rib extending upward from the upper surface of the blade and parallel spaced relation to the drawing edge of said blade, the side of the rib facing the drawing edge of the blade being at right angles to the upper face of theblade whereby said rib side forms a guide and said blade face a rest for the base of a draftsmans triangle.

In testimony whereof, I aflix my signature, in the presence of two witnesses.

RALPH A. ROI-IRIOH.

lVitnesses:

C. H. HILL, EDWARD C. SADOWSKI.

Copies of this patent may be obtained for five cents each, by addressing the "Commissioner of Patents, Washington. I). C. 

